# Questions tagged [seismic]

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### hi, any ideas how to convert Rcd and Dst seismic data into SEGY?

any ideas how to convert Rcd and Dst seismic data into SEGY?
43 views

### Zoeppritz equations

I have a question regarding zoeppritz equations. The equations from Telford are as follwoing: When trying to put in a matrix form, by converting amplitudes to reflection and transmission coefficients,...
1 vote
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### What happens to seismic waves reflected back to the surface?

What would be the behavior of seismic waves when it hit the geological media? The waves coming from a source hits different boundaries with different energies, the wave will be reduced in energy by ...
1 vote
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### SEG-2 vs SEG-Y file formats

I have limited experience with the different SEG file formats and I was hoping if someone could shed some light on the current preffered file formats used in software applications and for sharing ...
• 91
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### How to produce random numbers from seismic data?

I have read that the University of Chile uses seismic data to produce random numbers. (https://random.uchile.cl/randomness-beacon). Does seismic data real have randomness and if it so, which ...
• 163
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### How to quantitively compare two seismic waveform data?

Our group has built an Arduino-based device with an MPU6050 to act as our seismometer for our project, with the data being displayed on Amaseis. Our proctor demands that we quantitively assess its &...
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1 vote
35 views

### Estimation of velocity of the wave from seismic trace

How can seismologists estimate velocity (on the different layers) of the wave propogated through the earth , only from given seismic trace(s) ?
59 views

### If deterministic wavelet is better for well ties , why do people use statistical wavelet too for wellties?

Synthetic trace generated with deterministic wavelet gives a higher correlation with real seismics. Though it's more accurate for seismic well ties than statistical wavelet, but there is always an ...
116 views

### What is the purpose of wavelet extraction from the seismic trace?

I would love to know what exactly we can do with the extracted wavelet. What kind of information extracted wavelet can contain?
108 views

### Predicting rock type from seismic processing

In reflection seismology, we create a source with an airgun and then use receivers to register acoustic waves (an approximation) at the surface. From these measurements, we can predict a velocity ...
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### Is there a seismic discontinuity between the lithosphere and asthenosphere?

I've been learning about seismic discontinuities, mainly the 5 defined ones - Conorod discontinuity, Mohorovicic discontinuity, Repetti discontinuity, Gutenberg discontinuity, and Lehmann ...
• 183
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### Seismicity associated with post glacial rebound

Allied to the question: Why is relative sea-level falling in Hudson Bay?, where the surviving answers mention post glacial rebound. Is seismicity associated with post glacial rebound and if so what is ...
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1 vote
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### Are there specific layers in the subsurface that come before gas or oil?

Currently, I've started working on a geophysics project. More specifically, I'm trying to find gas and oil reservoirs in SEGY files using deep learning. I've been reading about seismic reflection ...
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1 vote
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### What are the boundary conditions for Navier's Equations of motion in seismic?

Navier's equations of motion in seismic have 3 solutions, according to how it is resolved (boundary conditions): for Vp (compression waves) for Vs (shear waves) for Vr (Rayleigh waves) I know the ...
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1 vote
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### Preconditions for stacking

Some of the requisite for stacking is that the noise and amplitudes need to be uncorrelated. Can someone explain to me why? Also is there a drawback for stacking?
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1 vote
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### Quality control in Seismic Acquisition - shot offset shift

I have a problem with seismic data where the minimum offset of the shot is not centered at the nearest receiver, this shift can be for 3 traces 2 or one and maybe more in the two sides !! So is there ...
1 vote
23 views

### Conversion of SEG-Y relative to MSL

I am working on the conversion of CSF file from SonarWiz into SEG-Y data. However, it comes back always related to the Sensor depth/altitude and never to the MSL. I have tried changing the bytes from ...
78 views

### Recent high seismic activity in Europe

It seems that Europe and the Mediterranean Sea have had high seismic activity in last six months. Major events which I remember are: 2020 Aegean Sea earthquake, magnitude of 7.0 Mww 29 December 2020:...
1 vote
142 views

### What would be the phase shift and polarity of a seismic wave upon reflection

What would be the phase shift and polarity of a seismic wave a) when it hit the free surface b)when the free surface reflection goes down and hit a reflector and returned to the receiver placed on the ...
• 111
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### Beam forming FK analysis of a seismic wave

So after reading alot of literature on source localization, I found out that FK analysis is one of the most widely used methods to determine source location without explicitly calculating the ...
1 vote
60 views

### How does uplift lead to onlapping?

I read in a paper that: Interpretation of 2-D seismic lines shows the lower to middle Patchawarra Formation onlapping onto paleostructural highs at approximately 270 Ma and again at 273 Ma, ...
1 vote
999 views

### How do we know the speed of S-waves (shear waves) in the Earth's inner core? Has this been measured?

Wikipedia's Seismic wave includes the plot below of the speed of S and P waves as a function of depth in the Earth. In the region of the outer core the speed of S-waves or shear waves is shown to be ...
• 7,122
1 vote
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### Q factor estimation from VSP

in seismic data processing there is a step of calculating the absorption represented By Q value which is Q factor , how we can estimate it from VSP ! thank you.
273 views

### stretch phenomena after NMO application on seismic data

after the NMO application we have stretch for far offset , i read a lot of articles but i can't have a complete idea how this phenomena is really created ! any one have a rich explanation ?
1 vote
108 views

### Where can I find broadband seismic reflection data?

or what type of companies should I contact to ask for the data? This data would be produced from Seismic Vibroseis survey trucks which are mostly used to locate oil and gas. I doubt most oil and gas ...
2k views

### Why do P waves have a higher velocity in the lower mantle than in the core even though the core has a much higher density?

I've just started teaching 9th grade Earth science and my students and I have noticed something about P and S wave depth vs velocity graphs. In the typical graph, eg: https://www.researchgate.net/...
1 vote
172 views

### Hydrophone/geophone sensor sensitivity - noise versus signal

Today, a student asked this question, and I was unable to answer it in a way that was understandable and accurate - even for myself. For seismic data acquisition projects, how are sensors able to '...
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### Using an accelerometer as a geophone to conduct a seismic survey

I am doing a capstone project for a sensor systems course and I would like to write a python program to acquire, process and present seismic data like that of seismic surveys. Is it possible using ...
1 vote
162 views

### Finding out actual dip and dip direction of refractor

We have two traveltive curves for first arrivals (direct and refracted) from a dipping refractor in the forward and reverse directions along a profile line. my question is: Is there a logical way (non-...
155 views

### Is it reasonable to approximate the swinging building (base of the building) during an earthquake to a simple harmonic motion?

I am thinking of making a model of swinging building during earthquake and study the methods to minimize the swinging. So does it even makes sense to approximate the swinging buildings (the base of ...
49 views

### Seismic velocity inversion & analysis

I attended at talk recently at the TGS office in Houston, TX, by Marianna Raunch. During this talk, a statement was made that for "very large" velocity inversions, semblance (or other similar ...
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### Wave train 200 m/s meaning

I ran a 60 m line intended for surficial seismic refraction. Energization with hammer. 12 (10 hz vertical 5 m spaced) geophones and 5 shots (15 m spaced). Record length 0.5 s. Thanks to a borehole ...
215 views

### wavelength of seismic wave with a gaussian source

I want to know how to get the wavelength/frequency of a seismic wave, if I only have a Gaussian source and the velocity (c = 4000m/s) of a medium given. e.g. for a Ricker wavelet it would be easy to ...
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### Seismic amplitude distribution

Recorded (or raw) and processed pre/post-stack seismic data (relative amplitudes) usually display a standard normal distribution, albeit with a very small amount of skewness. What would be possible ...
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### Seismic wavefield theory: velocity anisotropy

Does the reciprocity principle hold true in an anisotropic subsurface environment?
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### What is the vertical axis of this waveform shown in this tweeted IRIS GIF?

This IRIS tweet shows a video of siesmic waves from the recent M6.4 Earthquake in California rolling across the US. I've made a small GIF to give the idea but the "GIF" in the tweet shows the whole ...
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1 vote
236 views

### How to read Seismic Survey?

Recently I am tasked to create a POC on detection of patterns using a neural . But I am from a computer science background so I know about neural networks but I don't have any knowledge about geology ...
1 vote
228 views

### wave speed is smaller than both horizontal wave speed and vertical wave speed?

I am new to GIS and just get the idea of slowness. I can understand why people need the slowness in GIS rather than just the reciprocal of velocity. However, I feel the definition of slowness is weird ...
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1 vote
155 views

### reverse time migration for wave equation PDE using SBP-SAT

I'm stuck implementing a reverse time migration technique, the PDE(partial differential equation) being implemented is an acoustic wave equation, The numerical method being used is a FD(finite ...
1k views

### Travel Times for Seismic Wave Types - Why reflected t-x plot curves

I do not understand how the reflected wave in a seismic survey has a steepening slope (slows down) Please bear with me as I lay out my thoughts because I feel like I can grasp all of this except this ...
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1 vote
107 views

### Near-Surface Investigations: FWI vs. MASW

MASW is a common processing method for civil/geotechnical and even for oil/gas exploration (usually weathering static corrections) applications. In my experience, it seems to work well for most ...
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79 views

### Seismic data acquisition: reliability of high-bandwidth data

In my research, finding and understanding info relating to the lower end of (conventional) surface seismic data acquisition (i.e. 15 - 1 Hz) is relatively simple. However, when I look at specs for a ...
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1 vote
92 views

### Love-Wave Propagation

Love-waves cannot exist in a half-space. Layering must be present and there also must be accompanied impedance contrasts associated with the layering. Because layering naturally induces seismic ...
• 796
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### Difference between landslide waves and earth quake waves

I am new to this field, recently started working on landslide monitoring mainly in signal processing part. I have the following questions? 1.Will each land slide and every vibration have p wave, s ...
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1 vote
462 views

### Quality control in Seismic Acquisition - How much data is required?

When it comes to land or marine acquisition (oil exploration, for instance), I can see from literature that quality control (QC) is performed during the survey to ensure that the seismic traces ...
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### converting segd data to SU format using seismic unix

I tried to convert segd format to su format using seismic unix by below command: segdread tape=1.segd > 1.su but I have an error: ...
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### Basic petrophysics

The following question was inspired by Effective pressure or what is the effect of presssure?, which may be accessed here: https://inside.mines.edu/UserFiles/File/CRA/2005/...
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### DC component in Hilbert transform concept for seismic data

In The Leading Edge tutorial article Phase and the Hilbert transform (Purves 2014), there is the following line: So we apply a Hilbert transform by multiplying all negative frequencies by i and all ...
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